Biofouling has always been problematic in commercial and industrial water systems, such as cooling tower waters and air washers, because it can adversely affect heat transfer efficiency and fluid frictional resistance, thereby subsequently reducing production rates. Biofouling is also a problem in pulp and paper mill systems because the growth of microorganisms in papermachine fluids can adversely affect finished paper products, thereby requiring the papermachine to be shut down, resulting in the loss of productivity brought on by the down time of the machine. Furthermore, biofouling plays an important role in microbiologically influenced corrosion.
The presence of microorganisms in commercial and industrial waters cannot be totally eliminated, even with the excessive use of chemical biocides. The most common way to control biofouling is through the application of toxic chemical biocides such as chlorine, bromine, isothiazolones, glutaraldehyde or other antimicrobials. These biocides are added in an attempt to kill both planktonic and attached microorganisms.
Some microorganisms attach to inert surfaces forming aggregates with a complex matrix consisting of extracellular polymeric substances (EPS). This consortium of attached microorganisms and the associated EPS is commonly referred to as a biofilm. Biocides have difficulty penetrating biofilms and removing them from surfaces. Although excessive biocide dosages may be able to control biofouling, such use is costly and the presence of biocides in effluent waters is usually environmentally unacceptable.
Accordingly, it would be desirable to provide a method of inhibiting biofilm formation in commercial and industrial water systems which utilizes a low-cost, non-biocidal substance.